JPH01250670A - Manufacture of sheave for winding machine - Google Patents

Abstract

PURPOSE:To improve wear-resistance by flame-spraying Ni-base metal and Cr-base metal to a contacting surfaces between a sheave groove and a rope to form a flame spraying layer having a hardness of HB 200-300 and then applying laser light thereto make the flame spraying layer surface fine. CONSTITUTION:Flame spraying material of Ni-base metal, Cr-base metal or alloy of these metals and iron is flame-sprayed to the inner surface of a machined sheave groove 1a to form a flame spraying layer 2. The hardness of the flame spraying layer 2 is set to HB 200-300. Secondly, laser light is output from a laser generator, and energy required for conducting melting process to the flame spraying layer 2 is supplied and irradiated into the whole surface of the flame spraying layer 2. By this melting process, the flame spraying layer 3 is formed into a double structure comprising a molten flame spraying layer 2a on surface side and unmolten flame spraying layer 2b on base metal 1 side, wherein the unmolten flame spraying layer 2b is 20-30% of the entire thickness. Accordingly, the flame spraying layer 2 surface becomes fine so as to improve wear-resistance, and the unmolten flame spraying layer 2b functions as buffer material to prevent separation.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a method for manufacturing a sheave for a hoisting machine, and in particular can improve the wear resistance of a groove around which a rope is wound. The present invention relates to a method of manufacturing a sheave for a hoist.

(Prior art) In general, sheaves used in hoisting machines come into direct contact with the rope, which is a high-strength material, and transmit rotation and torque to the rope using frictional force to move the rope. It is desirable that the surface has high wear resistance, long life, and stable quality. In addition, in order to prevent wear of the sheave itself and damage to the rope, it is required that the hardness be within an appropriate range, and generally a hardness of HB200 to 300 is considered appropriate.

However, in the case of conventional cast iron products (for example, gray cast iron products), the sheave has a thick wall thickness, so if it is cast as it is, the solidification rate is slow, and as a result, the metal structure tends to become coarse and the hardness tends to decrease, and the hardness falls within the above-mentioned hardness range. It is difficult to keep it inside.

Therefore, some methods have been proposed for manufacturing sheaves with high wear resistance by adding special metals during casting and refining the metal structure to increase hardness.

(Problems to be Solved by the Invention) In the conventional method for manufacturing sheaves for hoisting machines, the added special metal is also easily affected by the temperature of the molten metal and the environment.
Casting defects such as segregation and pinholes are likely to occur. When segregation occurs, the segregated area becomes locally hard, and when pinholes occur, the rope is susceptible to abnormal wear due to the influence of the edges. , causing damage to the rope.

In addition, if the amount of special metal added is small, the hardness will decrease and cause wear of the lR part of the sheave, and if the amount added is large, the hardness will increase due to the precipitation of compounds, which will cause wear of the rope. becomes.

In addition, in cast iron products, the metal structure near the surface of the casting surface where the cooling rate is quick is the most refined and the hardness is highest, but in the case of a sheave, the area near the surface of the casting surface where the hardness is highest is removed due to the machining of the grooves. As a result, the lower hardness part of the rope becomes the contact surface of the rope, causing wear.

Further, the sheave only needs to have high hardness on the full surface that contacts the rope, and there is no need to increase the hardness of the entire sheave. If the hardness of the entire sheave is increased, the machinability is poor, resulting in poor workability and an increase in the manufacturing cost of the equipment.

The present invention was developed in view of the current situation, and it is possible to obtain the same machinability as conventional cast iron products such as gray cast iron products, and also to significantly improve the wear resistance of the contact surface of the groove with the rope. It is an object of the present invention to provide a method for manufacturing a sheave for a hoisting machine, which can extend the wear life by increasing the wear life.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides thermal spraying of a Ni-based metal, a Cr-based metal, or an alloy of these and iron on the contact surface with the rope of a groove provided on the circumferential surface of a sheave for a hoisting machine. The method is characterized in that a thermal sprayed layer having a hardness of HB200 to 300 is formed, and then this thermal sprayed layer is irradiated with a laser beam.

In the present invention, when irradiating the laser beam, it is preferable that only the surface side of the thermal sprayed layer is melted, and the sieve base material side is an unmelted thermal sprayed layer, and the thickness of the unmelted thermal sprayed layer is More preferably, it is about 20-30% of the total layer thickness.

(Function) In the method for manufacturing a sheave for a hoisting machine according to the present invention, a sprayed layer is formed on the contact surface of the groove with the rope, and the sprayed layer is irradiated with laser light.

As a result, the sprayed layer melts and the surface becomes dense, making it possible to significantly improve wear resistance. Also, at this time, by melting only the surface side of the sprayed layer and leaving the sieve base material side as an unmelted sprayed layer, and making the thickness of the unmelted sprayed layer approximately 20 to 30% of the thickness of the entire sprayed layer. There is no fear that the sheave base material will be hardened during laser beam irradiation, and the unmelted sprayed layer acts as a buffer, making it possible to prevent the sprayed layer from peeling off.

(Example) An example of implementing the present invention will be described below with reference to the drawings.

The sheave 1 for a hoisting machine according to the present invention is made of a conventional cast iron product, for example, a gray cast iron product, as shown in FIGS. 1 and 2.
As shown in the figure, a sheave groove 1a is machined on the circumferential surface. Then, as shown in FIG. 3, a metal spraying process is performed on the inner surface of the sheave groove 1a to form a sprayed layer 2.

The thermal spraying material for the thermal spraying layer 2 is a Ni-based metal, a Cr-based metal, or an alloy of these metals and iron.
The hardness is set to HB200-300.

Next, as shown in FIG. 4, the laser beam 4a output from the laser oscillator 3 is focused by a lens 5 to form
b, and the thermal sprayed layer 2 is irradiated with this laser beam 4b to melt the surface of the thermal sprayed layer 2.

The laser oscillator 3 is a device that supplies energy necessary for melting the sprayed layer 2, and in this embodiment, a carbon dioxide laser is used. The laser beam 4a output from this laser oscillator 3 is focused by a lens 5 as a laser beam 4b with an energy density that allows melting processing.
The sprayed layer 2 of the sheave 1 for a hoist is irradiated. At this time, the hoisting sheave 1 is moved by a moving device 6 shown in FIG.
The moving device 6 and the laser oscillator 3 are controlled by a control device 7.

That is, as shown in FIGS. 4 and 5, the moving device 6 moves the sieve for the winding machine so that the laser beam 4b is irradiated onto the molten layer q.1 along the sieve groove 1a to perform the melting process. 1 and moves the hoist sheave 1 in the Y direction in order to sequentially perform the melting process on the sprayed layer 2 in each sheave groove 1a. Further, the control device 7 controls the density, generation time, etc. of the laser beam 4b so as to make the melting processing conditions appropriate.
and controls the moving speed of the hoist sheave 1.

In this way, when the melting process of the sprayed layer 2 in the predetermined sheave groove 1a is completed, the laser oscillator 3 is stopped and the irradiation of the laser beam 4b is stopped, and the sheave 1 for the hoisting machine is moved by the moving device 6 into the Y direction. direction by a predetermined amount. Thereafter, the thermal sprayed layer 2 of the next sheave groove 1a is melted by the same procedure as described above.

As a result of this melting process, the sprayed layer 2 becomes as shown in FIG.
The molten sprayed layer 2a on the surface side and the unmelted sprayed layer 2b on the sieve base material side form a two-layer structure (one layer).By setting the melting treatment conditions appropriately, the thickness of the unmelted sprayed layer 2b can be adjusted. is set to about 20 to 30% of the total thickness of the sprayed layer 2.

FIG. 6 is a graph comparing the wear resistance of a sheave for a hoist manufactured by the method of the above example and a sheave for a hoist manufactured by adding a conventional special metal. The solid line graph shows the characteristics of the sheave for a hoisting machine according to this embodiment, and the characteristics of the sheave for a conventional hoisting machine.

As is clear from FIG. 6, by manufacturing a sheave for a hoist using the method of this embodiment, the wear resistance can be greatly improved.

Although not specifically explained in the above embodiment, the thermal spray layer 2
Since it is porous, the sprayed layer 2 may be impregnated with polytetrafluoroethylene or the like. And thereby, wear resistance can be further improved.

〔Effect of the invention〕

As explained above, the present invention forms a thermal sprayed layer with a hardness of HB200 to 300 by thermally spraying Ni-based metal, Cr-based metal, or an alloy of these and iron on the contact surface of the sheave groove with the rope. Next, this sprayed layer is irradiated with laser light, which makes the surface of the sprayed layer denser and improves wear resistance.The denser coating also reduces damage to the rope and improves reliability. be able to.

In addition, during the melting treatment with laser light, the sprayed layer on the sheave base material side is left unmelted, and the thickness of this unmelted sprayed layer is approximately 20 to 30% of the thickness of the entire sprayed layer. Hardening of the sheave base material during irradiation can be prevented, and the unmelted sprayed layer acts as a buffer material, making it possible to prevent the sprayed layer from peeling off.

[Brief explanation of the drawing]

FIG. 1 is a front view of a sheave for a hoisting machine showing an example of the implementation of the present invention, FIG. 2 is an enlarged sectional view taken along the line ■-■ in FIG. 1, and FIG. Figure 4 is a +1 diagram showing a device for melting the sprayed layer in the sheave groove, Figure 5 is an enlarged view of the main part of Figure 4, and Figure 6 shows the sheave for a hoisting machine according to the present invention and the conventional winding machine. It is a graph showing a comparison of wear resistance with an upper machine sheave. 1... Sheave for hoisting machine, 1a... Sheave groove, 2...
- Thermal spray layer, 2a... Molten spray layer, 2b... Unmelted spray layer, 3... Laser oscillator, 4a, 4b... Laser light. Applicant's agent Sato - Yuki 3 figures 4 figures Akira 5 figures

Claims (1)

[Claims] In a sheave for a hoisting machine having a groove on the circumference around which a rope is wound, the contact surface of the groove with the rope is thermally sprayed with Ni-based metal, Cr-based metal, or an alloy of these and iron to harden it. A method for manufacturing a sheave for a hoist, comprising forming a sprayed layer of HB200 to 300, and then irradiating the sprayed layer with laser light.